血管腔内放疗对经皮腔内冠状动脉成形术后再狭窄的防治

目的 :观察血管腔内放疗对经皮腔内冠状动脉成形术 (PTCA)后再狭窄的防治作用。方法 :选用家兔经颈外动脉插管对其颈总动脉实行了 PTCA,术后给予血管腔内放疗 (核通后装治疗计划 ) ,放射源中心轴外 3m m为处方剂量点 ,分别照射 10 Gy、2 0 Gy和 30 Gy。术后 4、12、2 4周取颈总动脉行病理检查。结果 :对照组PTCA后 4周 ,可见管腔狭窄 ,内膜不规则增厚 ,新生内膜内见大量棱形平滑肌细胞 ,排列紊乱 ,部分内弹力膜断裂。 10 Gy剂量放疗组未见有新生内膜 ,管腔无狭窄 ,内弹力膜完整 ,管壁略变薄。 2 0 Gy或 30 Gy放疗组管腔变大 ,管壁明显变薄 ,胶原组织和平滑肌细胞数量减少。 12周的病理结果与 2 4周时无明显差异。结论 :血管腔内放射治疗可明显抑制血管损伤后的组织增生 ,且抑制程度与剂量相关。

Experimental study of the intracavity radiotherapy in a post-PTCA restenosis model

Objective:To investigate the inhibit effect of hyperplasia of the endovascular brachytherapy for the restenosis after percutaneous transluminal coronary angioplasty(PTCA). Method:Endovascular brachytherapy with nucletron afterloder and plato TPS had been used at external carotid artery in a rabbit post PTCA restenosis model and 10, 20 and 30 Gy had been delivered to the point 3 mm from the axis of the source.Pathologic examination of the external carotid artery had been performed at 4, 12 and 24 weeks after PTCA. Result:A reduction of luminal area with marked fibrocellular neointimal hyperplasia, a disordered arrangement of fusiformed smooth muscle cells and part of the internal elastic membrane fragmentation were noted 4 weeks after PTCA in the control group. Neither fibrocellular neointimal hyperplasia nor reduction of luminal area was found in the 10 Gy treatment group. A slight asymmetric thinning of media was noted in the same group. The luminal area was increased, and thinning of media was evident with a marked reduction in smooth muscle cells and in collagen tissue,in the 20 Gy and 30 Gy treatment groups. There was no evident difference in histological examination between 12 weeks and 24 weeks. Conclusion:Intracavity radiotherapy can inhibit neointimal proliferation in the post PTCA restenosis model and the effect is associated with the dose.